// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_INTERPRETER_INTERPRETER_ASSEMBLER_H_
#define V8_INTERPRETER_INTERPRETER_ASSEMBLER_H_

#include "src/allocation.h"
#include "src/builtins/builtins.h"
#include "src/code-stub-assembler.h"
#include "src/globals.h"
#include "src/interpreter/bytecode-register.h"
#include "src/interpreter/bytecodes.h"
#include "src/runtime/runtime.h"

namespace v8 {
namespace internal {
    namespace interpreter {

        class V8_EXPORT_PRIVATE InterpreterAssembler : public CodeStubAssembler {
        public:
            InterpreterAssembler(compiler::CodeAssemblerState* state, Bytecode bytecode,
                OperandScale operand_scale);
            ~InterpreterAssembler();

            // Returns the 32-bit unsigned count immediate for bytecode operand
            // |operand_index| in the current bytecode.
            compiler::Node* BytecodeOperandCount(int operand_index);
            // Returns the 32-bit unsigned flag for bytecode operand |operand_index|
            // in the current bytecode.
            compiler::Node* BytecodeOperandFlag(int operand_index);
            // Returns the 32-bit zero-extended index immediate for bytecode operand
            // |operand_index| in the current bytecode.
            compiler::Node* BytecodeOperandIdxInt32(int operand_index);
            // Returns the word zero-extended index immediate for bytecode operand
            // |operand_index| in the current bytecode.
            compiler::Node* BytecodeOperandIdx(int operand_index);
            // Returns the smi index immediate for bytecode operand |operand_index|
            // in the current bytecode.
            compiler::Node* BytecodeOperandIdxSmi(int operand_index);
            // Returns the 32-bit unsigned immediate for bytecode operand |operand_index|
            // in the current bytecode.
            compiler::Node* BytecodeOperandUImm(int operand_index);
            // Returns the word-size unsigned immediate for bytecode operand
            // |operand_index| in the current bytecode.
            compiler::Node* BytecodeOperandUImmWord(int operand_index);
            // Returns the unsigned smi immediate for bytecode operand |operand_index| in
            // the current bytecode.
            compiler::Node* BytecodeOperandUImmSmi(int operand_index);
            // Returns the 32-bit signed immediate for bytecode operand |operand_index|
            // in the current bytecode.
            compiler::Node* BytecodeOperandImm(int operand_index);
            // Returns the word-size signed immediate for bytecode operand |operand_index|
            // in the current bytecode.
            compiler::Node* BytecodeOperandImmIntPtr(int operand_index);
            // Returns the smi immediate for bytecode operand |operand_index| in the
            // current bytecode.
            compiler::Node* BytecodeOperandImmSmi(int operand_index);
            // Returns the 32-bit unsigned runtime id immediate for bytecode operand
            // |operand_index| in the current bytecode.
            compiler::Node* BytecodeOperandRuntimeId(int operand_index);
            // Returns the 32-bit unsigned native context index immediate for bytecode
            // operand |operand_index| in the current bytecode.
            compiler::Node* BytecodeOperandNativeContextIndex(int operand_index);
            // Returns the 32-bit unsigned intrinsic id immediate for bytecode operand
            // |operand_index| in the current bytecode.
            compiler::Node* BytecodeOperandIntrinsicId(int operand_index);

            // Accumulator.
            compiler::Node* GetAccumulator();
            void SetAccumulator(compiler::Node* value);

            // Context.
            compiler::Node* GetContext();
            void SetContext(compiler::Node* value);

            // Context at |depth| in the context chain starting at |context|.
            compiler::Node* GetContextAtDepth(compiler::Node* context,
                compiler::Node* depth);

            // Goto the given |target| if the context chain starting at |context| has any
            // extensions up to the given |depth|.
            void GotoIfHasContextExtensionUpToDepth(compiler::Node* context,
                compiler::Node* depth, Label* target);

            // A RegListNodePair provides an abstraction over lists of registers.
            class RegListNodePair {
            public:
                RegListNodePair(Node* base_reg_location, Node* reg_count)
                    : base_reg_location_(base_reg_location)
                    , reg_count_(reg_count)
                {
                }

                compiler::Node* reg_count() const { return reg_count_; }
                compiler::Node* base_reg_location() const { return base_reg_location_; }

            private:
                compiler::Node* base_reg_location_;
                compiler::Node* reg_count_;
            };

            // Backup/restore register file to/from a fixed array of the correct length.
            // There is an asymmetry between suspend/export and resume/import.
            // - Suspend copies arguments and registers to the generator.
            // - Resume copies only the registers from the generator, the arguments
            //   are copied by the ResumeGenerator trampoline.
            compiler::Node* ExportParametersAndRegisterFile(
                TNode<FixedArray> array, const RegListNodePair& registers,
                TNode<Int32T> formal_parameter_count);
            compiler::Node* ImportRegisterFile(TNode<FixedArray> array,
                const RegListNodePair& registers,
                TNode<Int32T> formal_parameter_count);

            // Loads from and stores to the interpreter register file.
            compiler::Node* LoadRegister(Register reg);
            compiler::Node* LoadAndUntagRegister(Register reg);
            compiler::Node* LoadRegisterAtOperandIndex(int operand_index);
            std::pair<compiler::Node*, compiler::Node*> LoadRegisterPairAtOperandIndex(
                int operand_index);
            void StoreRegister(compiler::Node* value, Register reg);
            void StoreAndTagRegister(compiler::Node* value, Register reg);
            void StoreRegisterAtOperandIndex(compiler::Node* value, int operand_index);
            void StoreRegisterPairAtOperandIndex(compiler::Node* value1,
                compiler::Node* value2,
                int operand_index);
            void StoreRegisterTripleAtOperandIndex(compiler::Node* value1,
                compiler::Node* value2,
                compiler::Node* value3,
                int operand_index);

            RegListNodePair GetRegisterListAtOperandIndex(int operand_index);
            Node* LoadRegisterFromRegisterList(const RegListNodePair& reg_list,
                int index);
            Node* RegisterLocationInRegisterList(const RegListNodePair& reg_list,
                int index);

            // Load constant at the index specified in operand |operand_index| from the
            // constant pool.
            compiler::Node* LoadConstantPoolEntryAtOperandIndex(int operand_index);
            // Load and untag constant at the index specified in operand |operand_index|
            // from the constant pool.
            compiler::Node* LoadAndUntagConstantPoolEntryAtOperandIndex(
                int operand_index);
            // Load constant at |index| in the constant pool.
            compiler::Node* LoadConstantPoolEntry(compiler::Node* index);
            // Load and untag constant at |index| in the constant pool.
            compiler::Node* LoadAndUntagConstantPoolEntry(compiler::Node* index);

            // Load the FeedbackVector for the current function. The retuned node could be
            // undefined.
            compiler::TNode<HeapObject> LoadFeedbackVector();

            // Increment the call count for a CALL_IC or construct call.
            // The call count is located at feedback_vector[slot_id + 1].
            void IncrementCallCount(compiler::Node* feedback_vector,
                compiler::Node* slot_id);

            // Collect the callable |target| feedback for either a CALL_IC or
            // an INSTANCEOF_IC in the |feedback_vector| at |slot_id|.
            void CollectCallableFeedback(compiler::Node* target, compiler::Node* context,
                compiler::Node* feedback_vector,
                compiler::Node* slot_id);

            // Collect CALL_IC feedback for |target| function in the
            // |feedback_vector| at |slot_id|, and the call counts in
            // the |feedback_vector| at |slot_id+1|.
            void CollectCallFeedback(compiler::Node* target, compiler::Node* context,
                compiler::Node* maybe_feedback_vector,
                compiler::Node* slot_id);

            // Call JSFunction or Callable |function| with |args| arguments, possibly
            // including the receiver depending on |receiver_mode|. After the call returns
            // directly dispatches to the next bytecode.
            void CallJSAndDispatch(compiler::Node* function, compiler::Node* context,
                const RegListNodePair& args,
                ConvertReceiverMode receiver_mode);

            // Call JSFunction or Callable |function| with |arg_count| arguments (not
            // including receiver) passed as |args|, possibly including the receiver
            // depending on |receiver_mode|. After the call returns directly dispatches to
            // the next bytecode.
            template <class... TArgs>
            void CallJSAndDispatch(Node* function, Node* context, Node* arg_count,
                ConvertReceiverMode receiver_mode, TArgs... args);

            // Call JSFunction or Callable |function| with |args|
            // arguments (not including receiver), and the final argument being spread.
            // After the call returns directly dispatches to the next bytecode.
            void CallJSWithSpreadAndDispatch(compiler::Node* function,
                compiler::Node* context,
                const RegListNodePair& args,
                compiler::Node* slot_id,
                compiler::Node* feedback_vector);

            // Call constructor |target| with |args| arguments (not including receiver).
            // The |new_target| is the same as the |target| for the new keyword, but
            // differs for the super keyword.
            compiler::Node* Construct(compiler::Node* target, compiler::Node* context,
                compiler::Node* new_target,
                const RegListNodePair& args,
                compiler::Node* slot_id,
                compiler::Node* feedback_vector);

            // Call constructor |target| with |args| arguments (not including
            // receiver). The last argument is always a spread. The |new_target| is the
            // same as the |target| for the new keyword, but differs for the super
            // keyword.
            compiler::Node* ConstructWithSpread(compiler::Node* target,
                compiler::Node* context,
                compiler::Node* new_target,
                const RegListNodePair& args,
                compiler::Node* slot_id,
                compiler::Node* feedback_vector);

            // Call runtime function with |args| arguments which will return |return_size|
            // number of values.
            compiler::Node* CallRuntimeN(compiler::Node* function_id,
                compiler::Node* context,
                const RegListNodePair& args,
                int return_size = 1);

            // Jump forward relative to the current bytecode by the |jump_offset|.
            compiler::Node* Jump(compiler::Node* jump_offset);

            // Jump backward relative to the current bytecode by the |jump_offset|.
            compiler::Node* JumpBackward(compiler::Node* jump_offset);

            // Jump forward relative to the current bytecode by |jump_offset| if the
            // word values |lhs| and |rhs| are equal.
            void JumpIfWordEqual(compiler::Node* lhs, compiler::Node* rhs,
                compiler::Node* jump_offset);

            // Jump forward relative to the current bytecode by |jump_offset| if the
            // word values |lhs| and |rhs| are not equal.
            void JumpIfWordNotEqual(compiler::Node* lhs, compiler::Node* rhs,
                compiler::Node* jump_offset);

            // Updates the profiler interrupt budget for a return.
            void UpdateInterruptBudgetOnReturn();

            // Returns the OSR nesting level from the bytecode header.
            compiler::Node* LoadOSRNestingLevel();

            // Dispatch to the bytecode.
            compiler::Node* Dispatch();

            // Dispatch bytecode as wide operand variant.
            void DispatchWide(OperandScale operand_scale);

            // Dispatch to |target_bytecode| at |new_bytecode_offset|.
            // |target_bytecode| should be equivalent to loading from the offset.
            compiler::Node* DispatchToBytecode(compiler::Node* target_bytecode,
                compiler::Node* new_bytecode_offset);

            // Abort with the given abort reason.
            void Abort(AbortReason abort_reason);
            void AbortIfWordNotEqual(compiler::Node* lhs, compiler::Node* rhs,
                AbortReason abort_reason);
            // Abort if |register_count| is invalid for given register file array.
            void AbortIfRegisterCountInvalid(compiler::Node* parameters_and_registers,
                compiler::Node* formal_parameter_count,
                compiler::Node* register_count);

            // Dispatch to frame dropper trampoline if necessary.
            void MaybeDropFrames(compiler::Node* context);

            // Returns the offset from the BytecodeArrayPointer of the current bytecode.
            compiler::Node* BytecodeOffset();

        protected:
            Bytecode bytecode() const { return bytecode_; }
            static bool TargetSupportsUnalignedAccess();

            void ToNumberOrNumeric(Object::Conversion mode);

        private:
            // Returns a tagged pointer to the current function's BytecodeArray object.
            compiler::Node* BytecodeArrayTaggedPointer();

            // Returns a raw pointer to first entry in the interpreter dispatch table.
            compiler::Node* DispatchTableRawPointer();

            // Returns the accumulator value without checking whether bytecode
            // uses it. This is intended to be used only in dispatch and in
            // tracing as these need to bypass accumulator use validity checks.
            compiler::Node* GetAccumulatorUnchecked();

            // Returns the frame pointer for the interpreted frame of the function being
            // interpreted.
            compiler::Node* GetInterpretedFramePointer();

            // Operations on registers.
            compiler::Node* RegisterLocation(Register reg);
            compiler::Node* RegisterLocation(compiler::Node* reg_index);
            compiler::Node* NextRegister(compiler::Node* reg_index);
            compiler::Node* LoadRegister(Node* reg_index);
            void StoreRegister(compiler::Node* value, compiler::Node* reg_index);

            // Saves and restores interpreter bytecode offset to the interpreter stack
            // frame when performing a call.
            void CallPrologue();
            void CallEpilogue();

            // Increment the dispatch counter for the (current, next) bytecode pair.
            void TraceBytecodeDispatch(compiler::Node* target_index);

            // Traces the current bytecode by calling |function_id|.
            void TraceBytecode(Runtime::FunctionId function_id);

            // Updates the bytecode array's interrupt budget by a 32-bit unsigned |weight|
            // and calls Runtime::kInterrupt if counter reaches zero. If |backward|, then
            // the interrupt budget is decremented, otherwise it is incremented.
            void UpdateInterruptBudget(compiler::Node* weight, bool backward);

            // Returns the offset of register |index| relative to RegisterFilePointer().
            compiler::Node* RegisterFrameOffset(compiler::Node* index);

            // Returns the offset of an operand relative to the current bytecode offset.
            compiler::Node* OperandOffset(int operand_index);

            // Returns a value built from an sequence of bytes in the bytecode
            // array starting at |relative_offset| from the current bytecode.
            // The |result_type| determines the size and signedness.  of the
            // value read. This method should only be used on architectures that
            // do not support unaligned memory accesses.
            compiler::Node* BytecodeOperandReadUnaligned(
                int relative_offset, MachineType result_type,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);

            // Returns zero- or sign-extended to word32 value of the operand.
            compiler::Node* BytecodeOperandUnsignedByte(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);
            compiler::Node* BytecodeOperandSignedByte(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);
            compiler::Node* BytecodeOperandUnsignedShort(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);
            compiler::Node* BytecodeOperandSignedShort(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);
            compiler::Node* BytecodeOperandUnsignedQuad(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);
            compiler::Node* BytecodeOperandSignedQuad(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);

            // Returns zero- or sign-extended to word32 value of the operand of
            // given size.
            compiler::Node* BytecodeSignedOperand(
                int operand_index, OperandSize operand_size,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);
            compiler::Node* BytecodeUnsignedOperand(
                int operand_index, OperandSize operand_size,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);

            // Returns the word-size sign-extended register index for bytecode operand
            // |operand_index| in the current bytecode. Value is not poisoned on
            // speculation since the value loaded from the register is poisoned instead.
            compiler::Node* BytecodeOperandReg(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);

            // Returns the word zero-extended index immediate for bytecode operand
            // |operand_index| in the current bytecode for use when loading a .
            compiler::Node* BytecodeOperandConstantPoolIdx(
                int operand_index,
                LoadSensitivity needs_poisoning = LoadSensitivity::kCritical);

            // Jump relative to the current bytecode by the |jump_offset|. If |backward|,
            // then jump backward (subtract the offset), otherwise jump forward (add the
            // offset). Helper function for Jump and JumpBackward.
            compiler::Node* Jump(compiler::Node* jump_offset, bool backward);

            // Jump forward relative to the current bytecode by |jump_offset| if the
            // |condition| is true. Helper function for JumpIfWordEqual and
            // JumpIfWordNotEqual.
            void JumpConditional(compiler::Node* condition, compiler::Node* jump_offset);

            // Save the bytecode offset to the interpreter frame.
            void SaveBytecodeOffset();
            // Reload the bytecode offset from the interpreter frame.
            Node* ReloadBytecodeOffset();

            // Updates and returns BytecodeOffset() advanced by the current bytecode's
            // size. Traces the exit of the current bytecode.
            compiler::Node* Advance();

            // Updates and returns BytecodeOffset() advanced by delta bytecodes.
            // Traces the exit of the current bytecode.
            compiler::Node* Advance(int delta);
            compiler::Node* Advance(compiler::Node* delta, bool backward = false);

            // Load the bytecode at |bytecode_offset|.
            compiler::Node* LoadBytecode(compiler::Node* bytecode_offset);

            // Look ahead for Star and inline it in a branch. Returns a new target
            // bytecode node for dispatch.
            compiler::Node* StarDispatchLookahead(compiler::Node* target_bytecode);

            // Build code for Star at the current BytecodeOffset() and Advance() to the
            // next dispatch offset.
            void InlineStar();

            // Dispatch to the bytecode handler with code offset |handler|.
            compiler::Node* DispatchToBytecodeHandler(compiler::Node* handler,
                compiler::Node* bytecode_offset,
                compiler::Node* target_bytecode);

            // Dispatch to the bytecode handler with code entry point |handler_entry|.
            compiler::Node* DispatchToBytecodeHandlerEntry(
                compiler::Node* handler_entry, compiler::Node* bytecode_offset,
                compiler::Node* target_bytecode);

            int CurrentBytecodeSize() const;

            OperandScale operand_scale() const { return operand_scale_; }

            Bytecode bytecode_;
            OperandScale operand_scale_;
            CodeStubAssembler::Variable interpreted_frame_pointer_;
            CodeStubAssembler::Variable bytecode_array_;
            CodeStubAssembler::Variable bytecode_offset_;
            CodeStubAssembler::Variable dispatch_table_;
            CodeStubAssembler::Variable accumulator_;
            AccumulatorUse accumulator_use_;
            bool made_call_;
            bool reloaded_frame_ptr_;
            bool bytecode_array_valid_;
            bool disable_stack_check_across_call_;
            compiler::Node* stack_pointer_before_call_;

            DISALLOW_COPY_AND_ASSIGN(InterpreterAssembler);
        };

    } // namespace interpreter
} // namespace internal
} // namespace v8

#endif // V8_INTERPRETER_INTERPRETER_ASSEMBLER_H_
